1. Field of the Invention
The present invention relates generally to the field of display devices, and more particularly to screens and related hardware employed in rear projection display type environments.
2. Description of the Related Art
Current rear projection display devices typically employ a wide angle projection lens operating in connection with a series of reflective surfaces, such as mirrors, to direct light received from the wide angle projection lens to the back of the screen. This lens-mirror projection arrangement enlarges the image received at the wide angle projection lens. Such a rear projection display arrangement typically exhibits a width or thickness in the range of approximately 30-60 centimeters, and a weight in the range of approximately 10 to 50 kilograms for a large screen rear projection television type display where the screen diagonal is typically in the range of approximately 75 to 150 centimeters. In many environments, such a rear projection display device may be exposed to various adverse conditions, not the least of which is wear and tear in an active environment.
Certain rear projection display devices exhibit average or below average picture quality in certain environments. For example, such devices can be difficult to see when viewed from particular angles or when light varies within the environment or reaches extreme intensities in the environment. Light output and contrast is a constant issue in these types of environments and can negatively impact the viewing experience. Viewers are also becoming accustomed to enhanced types of displays, including but not limited to plasma displays or liquid crystal displays (LCDs), which can be more appealing than the traditional rear projection display but tend to cost significantly more. To address and improve rear projection quality in the mind of the more sophisticated consumer, certain enhanced lensing has been employed in the rear projection display system, but the aforementioned basic lens/reflector design remains generally intact and tends to be a limiting factor in overall picture quality and overall system thickness.
Specific examples of prior devices incorporating light guides to provide such attributes includes U.S. Pat. No. 4,116,739 to Glenn, entitled “Method of Forming an Optical Fiber Device”, and U.S. Pat. No. 5,381,502 entitled to Veligdan, entitled “Flat or Curved Thin Optical Display Panel.” The optical fiber device of U.S. Pat. No. 4,116,739 can be prohibitively expensive to make for use in the large screens for use in the home television market. The display panel of U.S. Pat. No. 5,381,502 suffers from an optical effect known as “keystoning” unless the projection system is significantly far from the input surface of the panel, which can be undesirable. An unacceptable image can result from a reasonably compact display panel and projection optics combination.
Weight, thickness, durability, cost, and quality are key considerations for rear projection television displays and display screens. It would be advantageous to offer a rear projection design that is lighter, thinner, less expensive, and offers an enhanced viewing experience over previous rear projection designs.